


came to this world a loaded handgun firing at random

by cashtastrophe



Series: goddamn, we missed the vein [9]
Category: Swapfell - Fandom, Undertale (Video Game)
Genre: Alternate Universe - Swapfell (Undertale), Feral Behavior, Gaster sucks out loud y'all, Incest, LITERALLY, M/M, Nonverbal Communication, Razz is Unsettled, Swapfell Papyrus (Undertale), Swapfell Sans (Undertale), dubcon
Language: English
Status: In-Progress
Published: 2019-02-02
Updated: 2019-02-02
Packaged: 2019-10-20 17:43:44
Rating: Explicit
Warnings: Graphic Depictions Of Violence, Rape/Non-Con
Chapters: 1
Words: 1,469
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17626757
Author URL: https://archiveofourown.org/users/cashtastrophe/pseuds/cashtastrophe
Summary: See, the really messed-up thing is? Sans is living in the house for, like...a solid two days before he even realizes the crazy old man has a kid.





	came to this world a loaded handgun firing at random

**Author's Note:**

> because i can't leave well enough alone: Swapfell :) :) :) 
> 
>  
> 
> :) :) :) dedicated to jessielefey who's at least partially to blame for encouraging this :) :) :)

See, the really messed-up thing is? Sans is living in the house for, like...a solid _two days_ before he even realizes the crazy old man has a kid.  
  
Which is terrible, actually, which says all kinds of deeply alarming things about Papyrus's daily routine—and which scares the absolute living _shit_ outta Sans the first time Gaster asks him to fetch some supplies from the basement storage locker without so much as the decency of a goddamn warning beforehand.  
  
Sans, like some kinda idiot, just opens the door easy as you fuckin' please, and is promptly greeted by something, for lack of a more astute observation, very much alive. He's greeted by something growling, something _snarling at him_ , nearly his size and little more than a blur of grimy off-white and orange rage barreling up the stairs towards him the instant he flips on the light.  
  
It practically knocks him over on the way past and Sans gets only a brief glimpse of wild eyelights, bared, rounded fangs, a single gunshot moment of _oh shit_ _, that looks a whole lot like a baby Gaster_ before the thing clocks he's even there. It lunges, rounds on him, and slams him into the concrete wall with one shoulder, like it's trying out for a goddamn football team.  
  
“Mother _fucker!_ ” Sans hisses, grabbing wildly for its flailing arms, at what looks like it might be a bruised, dirty wrist.  
  
It's skinny enough that he can grab hold even with his small hands, and luckily it's off-balance, so that he doesn't have too much trouble wrenching his prize the wrong way, twisting the thing's arm behind its back. It loses its _mind_ at the threat of being restrained though, positively thrashing in his arms, whipping its skull around and snapping its teeth at him like a dog.  
  
Which it— _he_ —isn't, although that would probably make the collar a little more reasonable. It's far too big for him, too bulky on his thin neck—a thick band of black leather studded with short brass spikes, clasped with a heavy buckle and trailing a short length of frayed rope behind. The rope's chewed at the end, ragged and damp-looking where the kid must have gnawed himself free.  
  
And now that Sans doesn't have his _metaphorical goddamn heart_ in his _metaphorical goddamn throat_ , it's marginally easier to tell that he has his other arm wrapped around the ribcage of a tiny, furious copy of his creator.  
  
“Oh, what the actual living _shit_ ,” Sans says. The little guy just squirms in response, entirely unhelpful, and tries to bite at the closest bit of Sans he can reach.  
  
It's only his clothed right shoulder, fortunately, because for a kid without his teeth even filed properly, those baby fangs still somehow manage to be _sharp_. He can't quite seem to get a proper grip on Sans himself, though, so he just kind of growls again and shakes his head viciously, worrying the heavy canvas of Sans's jacket between clenched jaws.  
  
He glares up at Sans with narrowed eye sockets as he gnaws at the fabric, his eyelights brilliant, furious little coals burning in the pitch depths. He's drooling a little.  
  
It's kinda cute.  
  
“Ah,” Gaster cuts in brightly from the top of the staircase, sounding not at all alarmed that his feral basement child is trying to bite Sans's arm off at the shoulder, “I see you've finally met Papyrus!” Like it was maybe just a schedule conflict preventing the two of them from interacting, instead of an entire floor of the house, a solid wooden door with half a dozen locks on the outside and a _rope_ tied around the kid's neck.  
  
“Papyrus,” Sans repeats faintly, eyelights locked on the young monster. The kid doesn't react to his own name at all. He doesn't even seem to hear it. He's still chewing on Sans's sleeve. “This is...Papyrus.”  
  
Because he knows the name. Of _course_ he knows the name. Undyne had offered him exactly three practical pieces of advice in all their time working side-by-side in the labs, two of which had been entirely unwelcome suggestions that he get laid by _literally anyone, Sans, when was the last time you actually left the fucking building, you're wound so tight it's stressing ME out—_  
  
The third had been hushed, as close to quiet as he suspected the fish-girl was physically capable of getting: “Don't bring up his kid. Like, _ever_. The official word is that it was some kind of accident in the lower levels dusted both him and the wife, but...I'm pretty sure she offed herself, y'know, and just took the kid with her. Can't say I blame her, really, being married to all _that_.” She'd huffed out a bitter little laugh. “But Doc loses his shit if you so much as mention Papyrus, so just...don't do it, okay?” And she'd patted his shoulder a little bit condescendingly, as though it was a real loss for Sans, not being able to chat with his boss about his dead kid.  
  
His dead kid, who is still drooling all the fuck over Sans's sleeve.  
  
His dead kid, who is apparently _very_ bad at actually staying dead.  
  
“Yes,” Gaster says, and it's low, calm, smooth as top-shelf liquor. It's cold. It's a clear warning Sans is treading dangerous waters. “Yes, this is _Papyrus_. Why do you say it like that?”  
  
“No reason at all, boss,” Sans answers, singsong. “Would you mind calling him off? I've kinda got plans for that hand later, if you know what I mean.”  
  
Gaster wrinkles his nasal cavity at the crass joke, but he does grab at the kid's collar with an ancillary hand. Jerks at it hard too, leather snapping tight on bruised bone, twisting until the young monster finally chokes, gags, and releases Sans with a frustrated whine.  
  
Papyrus actually cowers when he sees the figure blocking the doorway, though, drops down to his hands and knees like he's about to beg for Mercy—only then he sort of presses his belly to the filthy cement stairs and he just—  
  
He starts _crawling_ towards Gaster, doesn't he, like he's not aware that he's a monster at all, like he's an _animal,_ slinking low and apologetic and _entirely fucking terrible_ , keening this mournful little sound from the hollow of his ribcage the whole time that makes something new and painful wrench just beneath the frantic drumbeat of Sans's own soul when he realizes the kid isn't begging aloud because he _can't_ —  
  
“Thanks,” Sans says, numb, watching Papyrus nuzzle hopefully at the hem of Gaster's thick black sweater, lifting himself tentative onto his knees as he does it. When the action earns him no reprimand, when he isn't immediately knocked away, he reaches one small hand up slowly to hook a finger in Gaster's nearest belt loop.  
  
That seems kind of...not fine.  
  
Even from six stairs down, Sans can see that each one of his fingers has been individually wrapped in bandages that must have been clean once, though it's hard to tell anymore through the grime from the basement floor, the telltale muddy splotches of dried blood. The sleeves of his sweatshirt—grubby rust-orange, trimmed with black fur around the hood and hanging unzipped to his knees—are damp where they slouch over his knuckles, ragged, like he's been chewing at those, too. He's only wearing a half-shredded pair of black leggings and that collar otherwise, no shirt, his feet bare and black with filth.  
  
The basement is _freezing._ Neither of them seem to have noticed.  
  
“Why don't I make dinner,” Sans hears himself offer which is hey, yeah, _entirely fucking useless_. It's also the only option he'd been able to think of past an immediate wild, panicky urge to _bolt_ out of that basement and back to his tiny quarters at the Lab, where things had made some degree of sense, where monsters had kept, for the most part, to _appropriate professional boundaries._  
  
One of Gaster's hands—the real ones, the ones Sans never actually sees the motherfucker _use—_ drifts down to rest gently against the crown of Papyrus's skull. The kid almost purrs, he's so pleased.  
  
“That would be nice,” Gaster murmurs, scratching absent at Papyrus's coronal suture. He does not lift his eyelights from his son's.  
  
He does not comment at all on the fact that his son's other hand slides shyly up his femur. He says nothing when Papyrus's hesitant claws graze over the zipper of his jeans, though the movement is accompanied by a tilt of the kid's skull, clearly a question.  
  
Gaster says nothing, but Sans is getting pretty damn good at taking the guy's cues by this point. He goes upstairs. He makes dinner.  
  
What the fuck _else_ is he supposed to do?

**Author's Note:**

> child abuse, child neglect, literal child imprisonment, Gaster manages to get worse, Gaster keeps Slim in the basement, Razz finds Slim in the basement, everyone has a bad time. 
> 
>  
> 
> Eventually, this will actually be involved with the LBP verse proper--for now it's just its own little nightmare :) :) :)


End file.
